What the FDA labels say about taking them together
Dextromethorphan and memantine
Memantine's FDA label of November 1, 2018 names dextromethorphan in its drug interactions section; the dextromethorphan label PlainMeds reads does not name memantine.
Check it at the source: the dextromethorphan FDA label on DailyMed (effective August 27, 2026); the memantine FDA label on DailyMed (effective November 1, 2018, Actavis Pharma, Inc.).
What does the dextromethorphan label say about memantine?
Dextromethorphan's label (effective August 27, 2026) does not name memantine in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Good Sense Cough DM), L. Perrigo Company, effective August 27, 2026 (SPL set 5a2e9bef-42cb-4b72-9a26-c3ae71dcb4ea), via openFDA; the full label on DailyMed
What does the memantine label say about dextromethorphan?
Memantine label, drug interactionsUse with Other N-methyl-D-aspartate (NMDA) Antagonists The combined use of memantine hydrochloride with other NMDA antagonists (amantadine, ketamine, and dextromethorphan) has not been systematically evaluated and such use should be approached with caution.
Source: FDA drug label (memantine hydrochloride), NDA021487 (Abbvie), as published by Actavis Pharma, Inc., effective November 1, 2018 (SPL set 72973b46-f307-4a9e-8fb1-ad2cbccfd736), via openFDA; the full label on DailyMed
These are the labels' own sentences. PlainMeds does not grade interactions; a pharmacist or prescriber can say what they mean for one person's medicines.
Both medicines on the record
| Dextromethorphan | Memantine | |
|---|---|---|
| Labeled for | Cough and cold | Alzheimer's disease |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | $0.122 per unit 15 mg softgel | $0.063 per tablet 10 mg tablet |
| Shortage now | No current entry | No current entry |
Source: FDA NDC Directory, CMS NADAC of October 7, 2026 and the FDA Drug Shortage Database (FDA files October 8, 2026)
What next?
- Check more medicines together
- up to five at once